Exhibit 5.1

October 26, 2009

SolarWinds, Inc.

3711 South MoPac Expressway

Building Two

Austin, Texas 78746

Re: Registration Statement on Form S-1

Ladies and Gentlemen:

We have examined the Registration Statement on Form S-1 filed on October 26, 2009 by SolarWinds, Inc. (the “Company”) with the Securities and Exchange Commission in connection with the registration under the Securities Act of 1933, as amended, of shares of the Company’s common stock, $0.001 par value per share (the “Shares”), as may be subsequently amended (the “Registration Statement”). The Shares to be issued and sold by the Company pursuant to the Registration Statement are referred to herein as the “Company Shares” and the Shares to be sold by the selling stockholders identified in the Registration Statement pursuant to the Registration Statement, including Shares to be sold by the selling stockholders in the event of the underwriters’ exercise of an over-allotment option granted by the selling stockholders to the underwriters of the offering, are herein referred to as the “Secondary Shares.” We understand that the Shares are to be sold to the underwriters for resale to the public as described in the Registration Statement and pursuant to the underwriting agreement filed as an exhibit thereto. As the Company’s legal counsel, we have examined the proceedings taken and are familiar with the proceedings proposed to be taken by the Company in connection with the sale of the Shares.

As counsel for the Company, we have examined originals or copies, certified or otherwise identified to our satisfaction, of such documents, corporate records, certificates of public officials and other instruments as we have deemed necessary for the purposes of rendering this opinion. In our examination, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals and the conformity with the originals of all documents submitted to us as copies.

We are members of the bars of the State of California and the State of Texas, and we do not express any opinion herein concerning any law other than the Delaware General Corporation Law (including the statutory provisions, all applicable provisions of the Delaware Constitution and the reported judicial decisions interpreting the foregoing) and the federal law of the United States of America.

On the basis of the foregoing, we are of the opinion (1) that the Company Shares, when issued in accordance with the Registration Statement, will be validly issued, fully paid and nonassessable, and (2) that the Secondary Shares have been validly issued, fully paid and are nonassessable; provided, however, with respect to those shares to be sold by one of the selling stockholders that will be issued upon the exercise of options prior to the completion of the firm offering and the exercise of the underwriter’s over-allotment option, as the case may be, such shares will be validly issued, fully paid and nonassessable upon exercise in compliance with the terms of the options pursuant to which such shares are to be issued.

We consent to the use of this opinion as an exhibit to the Registration Statement, and we consent to the reference of our name under the caption “Legal Matters” in the prospectus forming part of the Registration Statement.

Very truly yours,

/s/ Wilson Sonsini Goodrich & Rosati

WILSON SONSINI GOODRICH & ROSATI

Professional Corporation